单链四苯酚基卟啉聚集状态的UV-Vis光谱分析

UV Visible Spectral Analysis on the Aggregation Forms of an Amphiphilic Porphyrin

目的研究单链四苯酚基卟啉分子Ｐ１在不同溶剂中的聚集行为．方法利用ＵＶ－Ｖｉｓ光谱法，根据Ｐ１的Ｓｏｒｅｔ带的位移及半峰宽，获得Ｐ１之间相互作用信息．结果与结论由于Ｐ１分别受控于分子３个局部结构的性质即十六烷基链的疏水性、３个苯酚基上ＯＨ基的亲水性及卟啉环易于自聚集的性质，其在水分子环境中以及在氯仿溶液中表现出复杂的聚集状态，在环己烷中，脂链及卟啉环与环己烷分子之间有良好的相容性，使得在一定的浓度范围之内，Ｐ１一直以单体形式存在．

Aim To study the effects of the concentrations of 5,10,15 tri( p hydrox ylphenyl) 20 ( p hexadecyloxyphenyl) porphyrin(a synthesis amphiphilic porphy rin), as well as solvent polarity on the aggregation forms of this porphyrin. Methods The information of interaction between the phorphyrins was obtained by the shifts and FWHHs of the Soret band according to UV vis spectra of the amphiphilic porphyrin in aqueous, chloroform and cyclohexane solutions at various concentrations. Results and Conclusion In aqueous solutions at lower concentra tions, the amphiphilic porphyrins exist as monomers. When its concentration is higher than 3 50×10 -6 mol·L -1 , it does not follow Beer′s law, indicating that the aggregations are formed. With continuously increasing its concentration, a blue shift of the Soret band from 428 nm to 410 nm takes place, which means that H type aggregates are formed by the self assembled action of porphyrin moiety. In cyclohexane solutions, the porphyrins are monomeric in a wide concentration range. In chloroform solutions with solvent polarity located between water and cyclohexane, the self assembled action of the porphyrin moiety results in the formation of face to face dimers or H type aggregates when the concentration is higher than 4 00×10 -6 mol·L -1 .